python Tk interface : NameError: global name 'box1' is not defined

Question

from Tkinter import *
import MySQLdb

def tran() :
 first= Tk()

 label1 = Label(first ,text="From")
 label1.pack()

 box1=Entry(first )
 box1.pack()

 label2=Label(first ,text="To")
 label2.pack()

 box2=Entry(first )
 box2.pack()

 label3=Label(first ,text="Amt")
 label3.pack()

 box3=Entry(first )
 box3.pack()

 Button1 = Button(first , text="Next", command=func3).pack() 


def func3() :
 conn = MySQLdb.connect (host = "localhost", user = "root", passwd = "natty", db = "dbms")
 cursor=conn.cursor()

 From=int(box1.get().strip())
 To=int(box2.get().strip())
 Amt=int(box3.get().strip())

 cursor.execute ("select bal from account where acc="+str(From)+"")

 a=cursor.fetchone()
 fromval=int(a[0])

 cursor.execute ("select bal from account where acc="+str(To)+"")

 b=cursor.fetchone()
 toval=int(b[0])

 fromval=fromval-Amt
 toval=toval+Amt

 cursor.execute("update account set bal="+str(fromval)+" where acc="+str(From)+"")
 cursor.execute("update account set bal="+str(toval)+" where acc="+str(To)+"")

 cursor.close ()
 conn.close ()

master = Tk()
Button3 = Button(master, text="Transaction", command=tran).pack()
mainloop()

screen shot

The Next button is not working .when i click "Next" button i'm getting the following error:

File "disp.py", line 24, in func3
    From = int (box1.get().strip())
NameError: global name 'box1' is not defined

Should i have to place the button inside the func3

I don't know if it is a copy/paste gotcha, but you really ought to indent python code with four spaces. That makes indentation errors easier to spot as a bonus. — Reinout van Rees, Apr 25 '12 at 13:23
Out of curiosity tried PythonTidy, here is the [prettified code](http://ideone.com/SCJIv). I had to replace double newlines too. — KurzedMetal, Apr 25 '12 at 14:09

SuperPrograman · Accepted Answer · 2012-04-25T14:53:54.650

Change your code to this:

from Tkinter import *

import MySQLdb

class App:

    def __init__(self, master):
        Button3 = Button(master, text="Transaction", command=self.tran).pack()

    def tran(self) :

        first = Tk()

        label1 = Label(first ,text="From")

        label1.pack()

        self.box1=Entry(first )

        self.box1.pack()

        label2=Label(first ,text="To")

        label2.pack()

        self.box2=Entry(first )

        self.box2.pack()


        label3=Label(first ,text="Amt")

        label3.pack()

        self.box3=Entry(first )

        self.box3.pack()

        Button1 = Button(first , text="Next", command=self.func3).pack() 


    def func3(self) :

        conn = MySQLdb.connect (host = "localhost", user = "root", passwd = "natty", db = "dbms")

        cursor=conn.cursor()

        From=int(self.box1.get().strip())

        To=int(self.box2.get().strip())

        Amt=int(self.box3.get().strip())
        cursor.execute ("select bal from account where acc="+str(From)+"")

        a=cursor.fetchone()

        fromval=int(a[0])

        cursor.execute ("select bal from account where acc="+str(To)+"")

        b=cursor.fetchone()

        toval=int(b[0])

        fromval=fromval-Amt

        toval=toval+Amt

        cursor.execute("update account set bal="+str(fromval)+" where acc="+str(From)+"")

        cursor.execute("update account set bal="+str(toval)+" where acc="+str(To)+"")

        cursor.close ()

        conn.close ()

master = Tk()

app = App(master)

master.mainloop()

I think that should work.

This will not work unless the functions are defined in classes which we have no reason to believe that they are. (This will just raise an error about `self` not being defined). Even if the functions are defined inside classes, `self` should be the first argument to the functions. — mgilson, Apr 25 '12 at 14:24

score 0 · Answer 2 · answered Apr 25 '12 at 13:19

0

box1 was defined inside of the tran() function, and thus (as the error message says) is not globally defined.

answered Apr 25 '12 at 13:19

Scott Hunter

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should i have to declare the box1 inside the func3 – Pradeesh tet Apr 25 '12 at 13:26
Declaring it in func3() will mean the reference causing the error will now be to a DIFFERENT box1 (the one local to func3). Look here for an explanation of sharing variables between functions: http://stackoverflow.com/q/423379/535275 – Scott Hunter Apr 25 '12 at 13:31
@user1190883 The link shared by ScottHunter is good and will probably get you where you need to go. A *better* way of doing it would be to pack all of this into a class in which case the shared information is passed via the class instance without the need for global variables. – mgilson Apr 25 '12 at 14:26

python Tk interface : NameError: global name 'box1' is not defined

2 Answers2